Shared Virtual Tunnels Supporting Mac Learning in Communication Networks

1. A method for packet switching and routing in a computer network that provides dual homed access, the method comprising: identifying a transport network, the transport network including switching devices that interconnect at least two separate access networks for transporting data traffic between end stations connected to the access networks, the transport network using tunnels to encapsulate and transmit data packets between respective switching devices; identifying a first switching device that connects a first access network to the transport network; identifying a second switching device that also connects the first access network to the transport network, the first and second switching devices providing the first access network with a dual homed connection to the transport network; creating a shared virtual tunnel that connects the first switching device to a third switching device within the transport network, the shared virtual tunnel also connecting the second switching device to the third switching device within the transport network, the shared virtual tunnel defining a single virtualized source device address representing both the first switching device and the second switching device; and in response to receiving a data packet from the first access network via the dual homed connection, encapsulating the data packet with the single virtualized source device address and transmitting the encapsulated data packet via the shared virtual tunnel to the third switching device, and wherein said shared virtual tunnel extends from a first edge device and a second edge device in a dual-homed arrangement to a third edge device, wherein said first edge device comprises said first switching device, wherein said second edge device comprises said second switching device, and wherein said third edge device comprises said third switching device.

2. The method of claim 1 , further comprising: wherein identifying the transport network includes the transport network supporting routing using multiple equal-cost paths; wherein encapsulating the data packet includes: in response to receiving the data packet at the first switching device, encapsulating the data packet with the single virtualized source device address and indicating a first routing path used by a forwarding plane of the third switching device; and in response to receiving the data packet at the second switching device, encapsulating the data packet with the single virtualized source device address and indicating a second routing path used by a forwarding plane of the third switching device.

3. The method of claim 2 , further comprising: executing tunnel learning of the virtual tunnel at a given switching device by identifying the single virtualized source device address as being linked to a given end station of a given access network; and storing at least two routing paths in a forwarding plane of the given switching device, the at least two routing paths being linked to the virtual tunnel.

4. The method of claim 1 , wherein identifying the transport network comprises the transport network using an Ethernet-based Virtual Private Network (EVPN) protocol to transport data within the transport network, the EVPN protocol including maintaining end station source and destination Media Access Control (MAC) addresses.

5. The method of claim 4 , further comprising: executing a MAC learning process on the switching devices by identifying end station locations linked to the single virtualized source device address without using routing paths corresponding to the single virtualized source device address as part of the MAC learning process.

6. The method of claim 1 , further comprising: wherein identifying the transport network comprises the transport network using Layer 2 of the Open Systems Interconnection (OSI) model; and wherein encapsulating the data packet with the single virtualized source device address includes indicating one of two routing paths, wherein a first routing path indicates a path using the first switching device, and a second routing path indicates a path using the second switching device.

7. The method of claim 6 , wherein the transport network includes using Shortest Path Bridging MAC (SPBM) according to an Institute of Electrical and Electronics Engineers (IEEE) 802.1ah standard.

8. A computer system comprising: a memory; a processor; a communications interface; an interconnection mechanism coupling the memory, the processor and the communications interface, the memory storing instructions that when executed by the processor cause the system to perform the operations of: identifying a transport network, the transport network including switching devices that interconnect at least two separate access networks for transporting data traffic between end stations connected to the access networks, the transport network using tunnels to encapsulate and transmit data packets between respective switching devices; identifying a first switching device that connects a first access network to the transport network; identifying a second switching device that also connects the first access network to the transport network, the first and second switching devices providing the first access network with a dual homed connection to the transport network; creating a shared virtual tunnel that connects the first switching device to a third switching device within the transport network, the shared virtual tunnel also connecting the second switching device to the third switching device within the transport network, the shared virtual tunnel defining a single virtualized source device address representing both the first switching device and the second switching device; and in response to receiving a data packet from the first access network via the dual homed connection, encapsulating the data packet with the single virtualized source device address and transmitting the encapsulated data packet via the shared virtual tunnel to the third switching device, and wherein said shared virtual tunnel extends from a first edge device and a second edge device in a dual-homed arrangement to a third edge device, wherein said first edge device comprises said first switching device, wherein said second edge device comprises said second switching device, and wherein said third edge device comprises said third switching device.

9. The computer system of claim 8 , the memory storing further instructions comprising: wherein identifying the transport network includes the transport network supporting routing using multiple equal-cost paths; wherein encapsulating the data packet includes: in response to receiving the data packet at the first switching device, encapsulating the data packet with the single virtualized source device address and indicating a first routing path used by a forwarding plane of the third switching device; and in response to receiving the data packet at the second switching device, encapsulating the data packet with the single virtualized source device address and indicating a second routing path used by a forwarding plane of the third switching device.

10. The computer system of claim 9 , the memory storing further instructions comprising: executing tunnel learning of the virtual tunnel at a given switching device by identifying the single virtualized source device address as being linked to a given end station of a given access network; and storing at least two routing paths in a forwarding plane of the given switching device, the at least two routing paths being linked to the virtual tunnel.

11. The computer system of claim 8 , wherein identifying the transport network comprises the transport network using an Ethernet-based Virtual Private Network (EVPN) protocol to transport data within the transport network, the EVPN protocol including maintaining end station source and destination Media Access Control (MAC) addresses.

12. The computer system of claim 11 , the memory storing further instructions comprising: executing a MAC learning process on the switching devices by identifying end station locations linked to the single virtualized source device address without using routing paths corresponding to the single virtualized source device address as part of the MAC learning process.

13. The computer system of claim 8 , the memory storing further instructions comprising: wherein identifying the transport network comprises the transport network using Layer 2 of the Open Systems Interconnection (OSI) model; and wherein encapsulating the data packet with the single virtualized source device address includes indicating one of two routing paths, wherein a first routing path indicates a path using the first switching device, and a second routing path indicates a path using the second switching device.

14. The computer system of claim 13 , wherein the transport network includes using Shortest Path Bridging MAC (SPBM) according to an Institute of Electrical and Electronics Engineers (IEEE) 802.1ah standard.

15. A computer program product including a non-transitory computer-storage medium having instructions stored thereon for processing data information, such that the instructions, when carried out by a processing device, cause the processing device to perform the operations of: identifying a transport network, the transport network including switching devices that interconnect at least two separate access networks for transporting data traffic between end stations connected to the access networks, the transport network using tunnels to encapsulate and transmit data packets between respective switching devices; identifying a first switching device that connects a first access network to the transport network; identifying a second switching device that also connects the first access network to the transport network, the first and second switching devices providing the first access network with a dual homed connection to the transport network; creating a shared virtual tunnel that connects the first switching device to a third switching device within the transport network, the shared virtual tunnel also connecting the second switching device to the third switching device within the transport network, the shared virtual tunnel defining a single virtualized source device address representing both the first switching device and the second switching device; and in response to receiving a data packet from the first access network via the dual homed connection, encapsulating the data packet with the single virtualized source device address and transmitting the encapsulated data packet via the shared virtual tunnel to the third switching device, and wherein said shared virtual tunnel extends from a first edge device and a second edge device in a dual-homed arrangement to a third edge device, wherein said first edge device comprises said first switching device, wherein said second edge device comprises said second switching device, and wherein said third edge device comprises said third switching device.

16. The computer program product of claim 15 , including further instructions stored thereon for processing data information, such that the further instructions, when carried out by a processing device, cause the processing device to perform the operations of: wherein identifying the transport network includes the transport network supporting routing using multiple equal-cost paths; wherein encapsulating the data packet includes: in response to receiving the data packet at the first switching device, encapsulating the data packet with the single virtualized source device address and indicating a first routing path used by a forwarding plane of the third switching device; and in response to receiving the data packet at the second switching device, encapsulating the data packet with the single virtualized source device address and indicating a second routing path used by a forwarding plane of the third switching device.

17. The computer program product of claim 15 , including further instructions stored thereon for processing data information, such that the further instructions, when carried out by a processing device, cause the processing device to perform the operations of: wherein identifying the transport network comprises the transport network using an Ethernet-based Virtual Private Network (EVPN) protocol to transport data within the transport network, the EVPN protocol including maintaining end station source and destination Media Access Control (MAC) addresses; wherein encapsulating the data packet with the single virtualized source device address includes indicating one of two routing paths, wherein a first routing path indicates a path using the first switching device, and a second routing path indicates a path using the second switching device; and executing a MAC learning process on the switching devices by identifying end station locations linked to the single virtualized source device address without using routing paths corresponding to the single virtualized source device address as part of the MAC learning process.

18. The method of claim 1 wherein said computer network uses Media Access Control (MAC) learning wherein the third switching device learns the single virtualized source device address for the shared virtual tunnel, the single virtualized source device address representing both the first switching device and the second switching device.

19. The computer system of claim 8 wherein said computer network uses Media Access Control (MAC) learning wherein the third switching device learns the single virtualized source device address for the shared virtual tunnel, the single virtualized source device address representing both the first switching device and the second switching device.

20. The computer program product of claim 15 wherein said computer network uses Media Access Control (MAC) learning wherein the third switching device learns the single virtualized source device address for the shared virtual tunnel, the single virtualized source device address representing both the first switching device and the second switching device.